REMEMBER WHEN: The marriage of Don (Jon Hamm) and Betty Draper (January Jones) was imperfect, but that was the whole point. (Photo: AMC)

By ADAM BUCKMAN

NEW YORK, April 5, 2012 — What’s wrong with “Mad Men” this season?

A couple of things, actually, but most notably: The defunct marriage of Don and Betty Draper, which, once upon a time, was the very heart of this show.

It’s gone and with it goes one of the great reasons for watching this show.

This finally occurred to me after watching the first two lifeless weeks of the new, fifth season of “Mad Men,” which is gracing us with its critically acclaimed presence after disappearing for 18 months.

The marriage of Betty and Don (January Jones and Jon Hamm) was once the centerpiece of this show. It was what the show was about, principally, whenever you’d try and describe it concisely.

What’s “Mad Men” about? you’d be asked. And you’d answer something like: Well, it’s about this guy, Don Draper, a quintessential Madison Avenue “ad man” of the 1960s struggling to balance his dual lives — one as a swashbuckling white-collar professional in midtown Manhattan, and the other as a family man with a pretty wife and two children who live far from the madding crowd in leafy Westchester.

And it didn’t hurt that the ad man and his wife were like the living, breathing versions of Ken and Barbie — perfection on the outside, while inwardly, they existed in a marriage fraught with tension. He was concealing his various extramarital affairs, though she had her suspicions; and she was feeling unfulfilled and lonely as a home-bound suburban housewife.

Even when Don’s affairs became known to Betty, it may have been possible to preserve the marriage, at least for the sake of the show. So what if that would make an already tense marriage even more tense. Tension happens to be a terrific ingredient to have around when you’re concocting a drama series for TV.

Now, with the two of them divorced and remarried to others, that whole situation’s been tossed out the window. Moreover, Don married a young, comely co-worker — which does away with another essential part of Don’s lifestyle: His ability to freely pursue his extramarital relationships in New York City, untethered and unobserved by his wife (in the era long before cellphones). Are we really supposed to believe that Don’s done with his philandering? And if he is, then is that part of the show now gone too?

It reminds me a little bit of “The Sopranos,” coincidentally a show on which “Mad Men” creator Matthew Weiner once worked. “The Sopranos” was also about a guy who struggled to balance his home life and “business” life, but in this case, he was a Mafia don who sought the help of a psychiatrist because he had deep-seated issues with his over-bearing mother.

But then, the actress who played the mother, Nancy Marchand, unfortunately died and Tony Soprano’s mother died with her. Of course, the show persisted after that, but the principal reason for telling Tony’s story in the first place was gone, and the show was never the same.

As if doing away with Don and Betty’s marriage wasn’t enough, now the makers of “Mad Men” have even done way with Betty — turning perhaps the most beautiful actress on TV into an overweight suburban housewife. Sure, I understand the storyline behind it, but is this storyline worth doing that to January Jones?

What else is wrong with “Mad Men,” three episodes into the new season (yes, that two-hour premiere night counted as episodes 501 and 502)?

A couple of things gleaned from Episode 503 last Sunday (April 1):

Some things just aren’t ringing true: The pot smoking, for example. Sure, we all know, or simply assume, that the 1960s saw a big rise in casual marijuana smoking, but mostly among the college generation. But for two consecutive weeks now, actual grownups have been seen smoking joints within full view of colleagues from work — most recently Harry Crane (Rich Sommer) backstage at the Stones’ concert last Sunday, and a week earlier, Ken Cosgrove (Aaron Staton), who casually mentioned that he’d like to go and smoke some “tea” at Don and Megan’s party.

Was casual pot-smoking of this kind really so sociably acceptable among actual adults in 1966? Though I’m no expert on this, that doesn’t seem accurate to me. It seems to me that for men like Don Draper, witnessing a colleague smoking dope in the 1960s would have raised suspicions that that co-worker was some kind of a druggie. That’s how “drugs” — even pot — were perceived back then, or so I’ve long thought.

Roger used a line in a conversation with Peggy Olson (Elisabeth Moss) that didn’t seem true to its era either. It was when he was instructing Peggy to make sure she hires a male copywriter for an open position on the Mohawk Airlines account. “Someone with a penis,” he said, describing the client’s preference.

Well, that sounds more like what a TV writer would compose for a character speaking in the present day. Certainly, the line was written for Roger Sterling (John Slattery) as an example of his own casual, crass chauvinism. But somehow I doubt a man in the 1960s would have put it that way. He just would have said Peggy needs to hire a man and that would be that. It’s today’s world in which the word “penis” is used with that kind of abandon (particularly on television, as a matter of fact). The usage here in “Mad Men” strikes me as careless writing.

Speaking of careless writing that should have been edited: The crack Betty’s husband, the political operative Henry Francis (Christopher Stanley), made about George Romney, then governor of Michigan and the father of the 2012 Republican presidential candidate Mitt Romney, was completely out of place and ill-considered. Why? Because we viewers all know that it represented a dig at Mitt Romney on the part of “Mad Men’s” writers and producers.

The line came when Henry, who apparently works for New York Mayor John Lindsay, told someone on the phone that he didn’t want Mayor Lindsay photographed with Gov. Romney at some sort of public appearance. “Romney’s a clown and I don’t want him standing next to him!” Henry declares.

Here’s why the line should not have been used: Because it makes us, the viewers, suddenly think of the present day while we’re supposed to be immersed in the world of 1966. For that reason alone, the producers should have resisted the temptation to include it.

And it should go without saying, but I’ll say it anyway: It was also an obnoxious political viewpoint — again, with contemporary implications — inserted into a TV show where it had no business being inserted.

I could go on about all the things wrong with “Mad Men” this season. But I’ll save them for next week. And who knows? Maybe the show will be back in top form this Sunday. And wouldn’t that be great?